Brain Renewal? Enhancing Aging Brains

An aging mind may be a fountain of wisdom, but an aging brain is not very good as a source of new neurons. As we age, quite apart from diseases like Alzheimer’s, we lose our ability to remember and to concentrate. It seems that in order to remain sharp, the brain has to regenerate itself by forming new neurons. While neurogenesis continues throughout life, it declines markedly in old age.

Photo credit: published under GNU Free Documentation License, uploaded 23 Sept 2007 by Ccrai008.

Research published today may suggest a way to change that. Scientists at the German Cancer Center in Heidelberg report on their work with mice. They identified a molecule called Dickkopf-1 or Dkk1 in the brains of old mice. When they blocked the production of Dkk1, old mouse brains began to create new brain cells.

“We released a brake on neuronal birth, thereby resetting performance in spatial memory tasks back to levels observed in younger animals,” said Ana Martin-Villalba in a press release from Cell Press, which published the results.

It turns out that clinical trials are already underway involving antibodies for Dkk1. These trials are not related to neurogenesis but to prevention of osteoporosis. What is learned there, however, may be directly helpful to the possibility that blocking Dkk1 is feasible, safe, and effective in countering the effects of declining neurogenesis, which includes both memory loss and depression.

The report concludes with these comments: “Our study raises the possibility that neutralization of Dkk1 might be beneficial in counteracting depression-like behavior and improving cognitive decline in the aging population….The contribution of newly generated young neurons to memory and affective behavior opens tantalizing opportunities for the prevention of affective impairments and age-related cognitive decline.”

These words are carefully chosen, first to caution against undue optimism but also to steer away from the idea of “human enhancement.” But unless we think of aging as a disease, what is envisioned here is clearly a form of enhancement. Normally aging human beings may, someday in the future, be treated not because they have a disease such as Alzheimer’s but because their memory is not as sharp as it once was or as retentive as they would like.

But labeling this an “enhancement” is not likely to dampen public interest. On the contrary, the enhancment potential of blocking Dkk1 is the very thing that is most likely to drive public support.

And that suggests we need to consider once again just what it is we say we do not like about enhancement.

The article is entitled "Loss of Dickkopf-1 restores neurogenesis in old age and counteracts cognitive decline" and appears in the February 7, 2013 issue of Cell Stem Cell.

Cognitive Enhancement: Campus Update

Use of drugs to boost academic performance is nothing new, but The Washington Post has just published a news story suggesting that use of these drugs is increasing on college campuses.

The story, written by Post reporter Jenna Johnson, refers to a study at the University of Maryland that suggests that students who take cognitive enhancers study less, party more, and have slightly lower grade point averages than their classmates. That suggests that their main purpose for using the drugs is stay competitive without letting studies get in the way of college.

There is little doubt, however, that the drugs are also being used by highly focused, academically competitive students in demanding programs. Their purpose: to add an edge to their hard work in order to stay in the top one or two percent of the competitive pile. As the Post reports, one name for these drugs is “Ivy League crack.”

The drugs in question are familiar enough—mostly Ritalin and Adderall. Students without prescriptions can easily buy these drugs from other students.

Should use of these drugs be treated as crimes? Or should those who wish to excel academically be allowed to use whatever means helps them achieve that end? For more on that debate, see the now-classic 2008 article in the journal Nature, in which prominent bioethicists such as Stanford’s Henry Greely argue for greater tolerance and openness.